Ember Engine Skill Version Hits A Limit For Now. I’m gonna say for Escalation the skill version with vile mask can easily solo up to Tier 0-4, Tier 6 was the highest I did but died a few times, Tiers 5-6 is where the time limit and heavy boss fights really limited the build. Now I believe I could get much higher on other missions vs others, but Tier 6 is where the brakes come on. If Ambush global is turned on I am positive Ember Engine could solo Tier 10 while hiding in cover 90% of the time, well maybe. Tier 4 was a sweet spot and netted me decent prototype drops 2-5, 23 tokens each completion in around 30-35 minutes. This is all with the laid back sit in cover and let the build burn everything, usually shooting just a few enemies for In Sync buff and popping armor off bosses.